Combining Acid- and Hydraulic-Fracturing Technologies Is the Key to
Successfully Stimulating the Orito Formation

Rozo, Rafael Eduardo; Páez, Francisco Javier Dóniz; Rojas, Alberto Mendoza; Milne, Arthur William; Soler, Diego Cano

doi:10.2523/104610-ms

Cited by 6 publications

(4 citation statements)

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“…In the case of applying the MC fluid in a propped fracturing treatment, the fluid sequence is similar that proposed by Rozo et al 6 However, unlike the case when a viscosified acid is used as a pre-pad in the calibration treatment after which the main treatment can be performed in a similar manner to a conventional treatment, the neutral pH of the viscosified MC fluid overcomes the potential operational drawbacks of using an acid pre-pad, which if not fully spent in the matrix, it can prematurely break the crosslinked polymer fracturing fluid. Premature breaking of the fracturing fluid can result in an underestimation of the fluid efficiency during the calibration treatment and/or prematurely screening out during the main treatment.…”

Section: The Pumping Schedulementioning

confidence: 87%

“…In the case of hydraulic fracturing treatments the movement of the fines would account for the dramatic reduction in the retained permeability after performing a static leakoff test (Fig. 6 In this scenario the use of a conventional HCl pre-flush ahead of the main acid treatment was not considered a practical option. This dramatic reduction in the matrix permeability of the fracture faces could in turn create a fracture face skin sufficiently high to actually negatively impact the productivity of the well.…”

Section: Initial Laboratory Testingmentioning

confidence: 99%

“…8) is present in the matrix which from the Energy Dispersive X-ray spectroscopy (EDX) (Fig. 6 However, the treatments were limited to areas of the reservoir where both the mineralogy and crude were compatible with an HF based stimulation fluid. • The action of the HF acid generated fines in the matrix (Fig.…”

Section: Conventional Acid Systemsmentioning

confidence: 99%

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An Alternative Solution to Sandstone Acidizing Using a Nonacid Based Fluid System With Fines-Migration Control

Rozo¹,

Páez²,

Rojas³

et al. 2007

Proceedings of SPE Annual Technical Conference and Exhibition

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fax 01-972-952-9435. AbstractThe Caballos formation is thick laminated sandstone with less than 10% of total clays and permeability ranging from 20 mD to as high as one Darcy. However, the production from this formation is often limited due to the low critical flow rate in the matrix (less than 1 mL/min) and associated fines migration as shown in several tests.Historically matrix acidizing and hydraulic fracturing treatments in this formation have only been partially successful due to destabilization of the clays and inadequate fines stabilization, along with the incompatibility of the crude oil with many conventional acid systems.In order to overcome the limitations associated with the use of conventional acid systems an extensive laboratory study was conducted using a non-acid based stimulation fluid. The base fluid selected was a newly developed chelating agent that is very tolerant to high concentrations of both carbonate and aluminosilicates, and iron and zeolite bearing minerals. By including acid salts in the fluid it proved possible to develop a fluid system with the equivalent dissolving power of a conventional 6:1.5 (HCl: HF) mud acid, even at temperatures as low as 180 o F. Testing also showed that the fluid was capable of controlling fines migration and that a scale inhibitor could be included in the formulation, while the fluid system exhibited excellent compatibility with the formation fluids throughout the field.The newly developed non-acid fluid system provides some unique advantages for matrix acidizing applications and in particular for stimulating the Caballos formation 1) Minimizes the risk of secondary and tertiary precipitation due to the nature of the chelating agent 2) A single treating fluid instead of the multiple fluids/stages used in a conventional treatment 3) Greatly reduced sludging and emulsion tendencies compared to conventional acid systems (without the addition of surfactants or demulsifiers) and much lower corrosion rates 4) The ability to stabilize fines present in the matrix 5) Allows for a scale inhibitor to be included in the treating fluid 6) Reduces the logistics and HSE risks during the execution of the treatment.This paper reviews the laboratory testing including an extensive core flow testing performed to develop a new nonacid treating fluid for both matrix acidizing and dual stimulation applications in the Caballos formation and its implementation in the field, illustrated with case studies and production data.

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Section: The Pumping Schedulementioning

confidence: 87%

Section: Initial Laboratory Testingmentioning

confidence: 99%

See 1 more Smart Citation

An Alternative Solution to Sandstone Acidizing Using a Nonacid Based Fluid System With Fines-Migration Control

Rozo¹,

Páez²,

Rojas³

et al. 2007

Proceedings of SPE Annual Technical Conference and Exhibition

Self Cite

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show abstract

“…So the propped fracturing was introduced in some carbonate field, because of ability of deeper penetration and longer duration of fracture with proppant [1,2] , but its ability of connecting natural fracture or fissure is poor because the fracturing fluid is inert fluid, even though the fracture of fissure is essential to the productivity in carbonate formation. In this condition, not like the previously divided into 2 stages [3] , the technique which can combine the advantages of acid fracturing and propped fracturing was studied. The novel surface cross-linked acid (SXA) makes the technique possible, because it can not only readily carry proppant but also react with the carbonate formation to eliminate the formation damage and connect the natural fracture, which can maximize the drainage area and the stimulation reservoir volume (SRV), which has been proved to benefit the well productivity [4] .…”

Section: Introductionmentioning

confidence: 99%

Propped Fracturing with a Novel Surface Cross-linked Acid in High Temperature Deep Carbonate Formation

Ding

et al. 2010

All Days

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Acid fracturing, as a conventional and effective stimulation method, has been widely used in carbonate formation. But because of serious acid leak-off and rapid acid/rock reaction speed, the length of effective acid etched fracture is always restricted, even the high viscosity acid and emulsified acid were applied; besides, the effective duration of etched fracture was short, especially in deep well. The propped fracturing can supply longer fracture and long-term effective duration, but its ability of connecting natural fracture or fissure is poor because the fracturing fluid is unreactive with the formation. So the propped fracturing with a novel surface cross-linked acid (SXA) is proposed, because it can not only realize long fracture length/deep penetration, but also connect more natural fracture/fissure to maximize the permeable area as possible.In order to realize the technique, a novel temperature-stability and shearing resistance delayed cross-linked acid (SXA) was developed to qualify for the fracturing treatment. Meanwhile the effect of HCl on one high strength ceramic proppant was also studied, and the results showed the crush resistance and conductivity of proppant is unaffected. So the SXA and the acidresisting proppant provide the basis for acid propped fracturing, and a comprehensive fracturing technique was developed.Acid propped fracturing with SXA was processed in the carbonate formation with depth > 5000m and temperature >140℃. A volume of 36.2m 3 proppant was successfully pumped into the formation with the maximal proppant concentration exceeding 450kg/m 3 . The net pressure matching indicated that the propped fracturing created long conductive fracture and realized deep penetration. The new technique provided a new and broader option of carbonate stimulation.

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An Alternative Solution to Sandstone Acidizing Using a Nonacid-Based Fluid System with Fines-Migration Control

Rozo¹,

Paez²,

Rojas

et al. 2007

SPE Annual Technical Conference and Exhibition

View full text Add to dashboard Cite

The Caballos formation is thick laminated sandstone with less than 10% of total clays and permeability ranging from 20 mD to as high as one Darcy. However, the production from this formation is often limited due to the low critical flow rate in the matrix (less than 1 mL/min) and associated fines migration as shown in several tests. Historically matrix acidizing and hydraulic fracturing treatments in this formation have only been partially successful due to destabilization of the clays and inadequate fines stabilization, along with the incompatibility of the crude oil with many conventional acid systems. In order to overcome the limitations associated with the use of conventional acid systems an extensive laboratory study was conducted using a non-acid based stimulation fluid. The base fluid selected was a newly developed chelating agent that is very tolerant to high concentrations of both carbonate and aluminosilicates, and iron and zeolite bearing minerals. By including acid salts in the fluid it proved possible to develop a fluid system with the equivalent dissolving power of a conventional 6:1.5 (HCl: HF) mud acid, even at temperatures as low as 180°F. Testing also showed that the fluid was capable of controlling fines migration and that a scale inhibitor could be included in the formulation, while the fluid system exhibited excellent compatibility with the formation fluids throughout the field. The newly developed non-acid fluid system provides some unique advantages for matrix acidizing applications and in particular for stimulating the Caballos formation 1) Minimizes the risk of secondary and tertiary precipitation due to the nature of the chelating agent 2) A single treating fluid instead of the multiple fluids/stages used in a conventional treatment 3) Greatly reduced sludging and emulsion tendencies compared to conventional acid systems (without the addition of surfactants or demulsifiers) and much lower corrosion rates 4) The ability to stabilize fines present in the matrix 5) Allows for a scale inhibitor to be included in the treating fluid 6) Reduces the logistics and HSE risks during the execution of the treatment. This paper reviews the laboratory testing including an extensive core flow testing performed to develop a new nonacid treating fluid for both matrix acidizing and dual stimulation applications in the Caballos formation and its implementation in the field, illustrated with case studies and production data. Introduction In the Orito field in the south of Colombia the most prolific reservoir is the Caballos Formation, 250-ft thick interbedded fluvial/deltaic and marginal marine sands that originally contained more than 700 million bbl of oil in place. Due to distinct changes in the vertical lithology the reservoir is divided into four distinct flow units or layers A, B, C and D in ascending order shown in Fig 1. Furthermore, the production of the wells along with a petrographic and petrophysical study has shown that there are two distinct zones of markedly different reservoir quality. The lower zone - layer A, is a much better quality reservoir than the upper zone. Layer A is a well sorted sand with kaolinite present in the pore spaces. The porosity and klinkenberg permeability varies from 12 to 14 % and from 100 to 300 mD, respectively. While, the upper zone - layers B, C and D - is a much poorer quality reservoir. A single facies of poorly sorted and loosely packed quartz with kaolinite in the inter-granular spaces. The porosity in this upper zone is predominantly intergranular ranging from 11 to 12 % and the klinkenberg permeability from 5 to 150 mD, (Fig. 2). In addition, due to the presence of a number of major and minor faults the reservoir is compartmentalized. The complexity of the stratigraphy reflected in the marked changes in the quality of the reservoir and the properties of the oil in place, across the field. Due to the fractional composition of the oil, the properties of the crude oil also vary between the different layers, independently of the location of the wells on the structure.

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Combining Acid- and Hydraulic-Fracturing Technologies Is the Key to Successfully Stimulating the Orito Formation

Cited by 6 publications

References 0 publications

An Alternative Solution to Sandstone Acidizing Using a Nonacid Based Fluid System With Fines-Migration Control

An Alternative Solution to Sandstone Acidizing Using a Nonacid Based Fluid System With Fines-Migration Control

Propped Fracturing with a Novel Surface Cross-linked Acid in High Temperature Deep Carbonate Formation

An Alternative Solution to Sandstone Acidizing Using a Nonacid-Based Fluid System with Fines-Migration Control

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